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uni'wissen 01(3)-2011_ENG

Prof. Dr. Reto Gieré has worked at the Section for Mineralogy-Geochemis- try at the Department of Earth Sciences since 2004. Other stations of his career include Purdue University in Indiana, USA, the Uni- versity of Basel, Switzer- land, the University of Brit- ish Columbia in Vancouver, Canada, and the Carnegie Institution in Washington, USA. He is also a fellow at the Geological Society of London and the Mineralogi- cal Society of America. His research interests include atmospheric dust particles, environmental contamina- tions, and the storage of highly radioactive waste. scope to ascertain whether the particles have penetrated into the cell, and if so what part of it. The foreign matter can reach the cytoplasm or the nucleus, and in the worst case they can cause damage there. When this happens, the lung sends out antibodies so the cells can de- fend themselves against the foreign matter. The scientists can then measure the signals created during this process. The Smaller, the More Persistent The size of the dust particles is an important factor, and the differentiation between coarse and fine particles has sparked much controver- sy: “Politicians and the media often speak of fine particles in general,” complains Gieré, “without knowing how fine a particle actually has to be to earn this name.” All dust particles larger than 2.5 micrometers (0.0025 millimeters) are classi- fied as coarse particles, while particles with a size of 2.5 micrometers or less are characterized as fine particles, and those that are smaller than 100 nanometers (0.0001 millimeters) are catego- rized as nanoparticles or ultrafine particles. The smaller a particle is, the more of that particle a fleck of dust will contain. Moreover, fine particles float around in the atmosphere longer than coarse particles. Only when it rains is the air washed free of fine particles. But it is not only their persistence that makes the smaller parti- cles a greater threat for human health; they can also inflict more damage due to their small size. Dust particles that are smaller than 2.5 micro­ meters can accumulate in the alveoli in our lungs and once they make it there, we can’t get them back out of our bodies. Coarse particles, on the Further Reading Gieré, R. (2010): Atmospheric Particles. ­Elements 6, 201– 272. Gminski, R./Decker, K./Heinz, C./Seidel, A./ Könczöl, M./Goldenberg, E./Grobéty, B./­ Ebner, W./Gieré, R./Mersch-Sundermann, V. (2010): Genotoxic effects of three selected black toner powders and their dimethyl sulf­ oxide extracts in cultured human epithelial A549 lung cells in vitro. In: Environmental and Molecular Mutagenesis, DOI: 10.1002/em.20621. other hand, can’t make it that far into our respi- ratory tract because they irritate our throats, in- ducing us to cough them out. The team led by Gieré and Prof. Dr. Volker Mersch-Sundermann from the Freiburg Univer­ sity Medical Center has already published the first sobering results: The researchers’ in vitro tests demonstrated that particles from black ink cartridges inflict changes in the cell nucleus and thus have a genotoxic, i.e., gene-changing, effect on the human lung. This could lead to mutations or cancer, but the research team cannot yet say for sure. Gieré and his colleagues still need to conduct more experiments to analyze all of the effects of the various types of dust. In order to be successful, these experiments must transcend the boundaries of traditional scientific disciplines. Freiburg provides ideal conditions for this multi- disciplinary research, says the mineralogist. By no means does he intend to spread panic: “How- ever, it is important to point out concrete dangers, because only so can we react to them.” Microscopic image of a sample of atmospheric dust collected in Mainz. A dust analysis can differentiate between various types of particles on the basis of their optical characteristics, allowing scientists to determine their origins. Graphic: German Weather Service/Dietze 7